Engine Swap, custom pan vs custom subframe
 

Hypothetical question of the week time.

Say you were going to buy an engine swap kit would you rather have a custom cast oil pan and use the stock subframe and have the kit mostly consist of engine mounts. Or would you rather a tubular subframe that uses all NB geometry, use an OEM oil pan and stock style mounts from the motor in question?

Pan pros
$400 cheaper

Pan cons
Ships from europe

Subframe pros
lighter
stiffer

Subframe cons
$400 more expensive
Might not be legal in your racing class

The 3rd option is throw money to the wind, spend an extra $400 over the subframe option to combine it with the custom pan and mount the motor an extra inch lower.

Pan cons seem less.

It all depends on budget. Assuming the fitment and quality of both options are adequate.

Why cast pan? Why not sheet metal? There are a bunch of people that make pans in the US (Milodon, Moroso, Canton, etc) and I would assume all of them can do a short run of custom pans.

As long as the pan doesn't have a compromise that we're not seeing cheaper is better.

Pan is a structural member of this particular engine. I'd rather not have a thin sheet steel pan doing that job. The only compromise I can see for the pan option is that doing the subframe option you gain a stiffer and lighter by ~10lbs subframe. And $4/lb is worth it to a lot of people. But if you go with the oil pan option then it would still work with an off the shelf tubular subframe.

No reason to redesign the wheel on the subframe part. If I did a swap and I had the option to keep OEM everything besides the engine it would be a no brainer. One of the FE3 guys actually swapped in a 1.6 in a day when he blew his FE in california.

Assuming you're starting with a street car engine, probably a custom oil pan. The ability to improve oil control, probably better QC, and simpler assembly makes a solid argument. Now if using the stock subframe requires a less optimized oil pan, that would be bad. Also, if it's really designed for track work options for a dry sump (and maybe the new subframe to go with it) would be a vote towards a new pan(s).

Does this imaginary tubular subframe have stock Miata engine mount points? That would permit the "return to stock".

It could. It seems like the most sensical thing to do would be to just offer 2-3 height mounts or mount adapter that all work with the stock miata subframe mounts. 1 is stock subframe and low pro pan and also tubular subframe and OEM pan, low pro pan + tubular subframe, drysump pan + tubular subframe.

It would make sense to produce the subframe with stock mount locations and the ability to accommodate a variety of engines. Then produce mounts to adapt each engine to the subframe. That's win for the buyer and builder. Otherwise you have a custom oil pan that fits one engine.

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This escalated quickly!

To the OP. Your heart is in the right place but your R&D (mostly the "R") needs some catching up. If the price was right, I'd try one of your manifolds (and a reasonably-sized DP) just for shits 'n giggles. Other than that - do what you like to do. That brick wall named "REALITY" comes at you quick!

"Related Threads" strikes again...

Three year old thread, please move along :gtfo:

@Robb M., welcome to your first angry-tag.

I emailed your bosses about a week ago, and they assured me that they were rolling out Related Threads to all 130+ IB properties, regardless of whether or not we wanted it.

This is what you get when you get Related Threads. You get people mis-replying to the related thread instead of the actual thread.

Whether or not it will have any effect, I'll continue to tag you in every single "related thread" mis-reply, just so you can be as annoyed as I am when I have to re-read a 3.5 year old thread bumped due to your employer's desire to artificially increase page view metrics.

Welcome to MT.net

@Savington fair. I dislike related threads myself, it's the first thing I turn off in the userCP. You're definitely not the only one to make this complaint known and I believe the tech guys are whipping up a fix however turkey week slowed them down.

@Robb M. , I don't know how long you've been lurking here, but when the last major update rolled out a few weeks ago, there was a lot of anger, most of it justified.

A few things were legitimately broken, however the much larger issue seemed to be new functionality which was "working as intended," but which made the over all user experience worse.

The new composition window is a prime example of this. Much harder to compose properly formatted messages, and the buttons to expand the text entry window are much missed, as it's impossible to correctly click and drag on the window to resize it when on a mobile device. (I vastly prefer the "desktop" site when using my phone or tablet.) We used to have the option to use the "classic" editor, but that was recently taken away.